In Internet Protocol (IP) multicast, an IP data packet is transmitted to all devices in a multicast group (Multicast Group) by using a specific multicast address. In a basic method for the IP multicast, when a device sends data to a group of devices, instead of sending the data to each of the devices, the device sends the data to a specific multicast address, and all the devices that join the multicast group can receive the data. For a transmit-end device, data needs to be sent only once to all receivers, thereby greatly reducing load of a network and a sender.
The IP multicast serves as a communication mode parallel to unicast and broadcast, and more importantly, the IP multicast may be further used to conveniently develop some new value-added services including Internet information services such as live television, tele-education, tele-medicine, Internet radio, multimedia conferencing, and video surveillance.
In the prior art, IP multicast protection is performed by using a Protocol Independent Multicast (PIM) fast reroute (FRR) technology. However, due to lack of an effective fault detection technology for a multicast path, it is difficult to perform patch switching quickly.